Smart multiplexed medical laser system

ABSTRACT

A system includes a laser catheter and a rotating optical member to receive a laser beam along an optical path and rotate to a selected position to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter, wherein a distal end of the laser catheter irradiates an endovascular structure.

FIELD

The disclosure relates generally to endovascular devices andparticularly to laser catheters.

BACKGROUND

Laser energy can be transmitted through multiple optical fibers housedin a relatively flexible tubular catheter inserted into a body lumen,such as a blood vessel, ureter, fallopian tube, cerebral artery and thelike to remove obstructions in the lumen. Catheters used for laserangioplasty and other procedures can have a central passage or tubewhich receives a guide wire inserted into the body lumen (e.g., vascularsystem) prior to catheter introduction. The guide wire facilitates theadvancement and placement of the catheter to the selected portion(s) ofthe body lumen for laser ablation of tissue.

In designing a laser catheter, there are a number of considerations.

For example, laser energy should be controllably and selectivelydelivered onto single fibers or smaller sub-bundles of subsets of fibersthat make up the total number of fibers that are incorporated into thedevice. This can reduce the overall impact of heat or acoustic shockthat can damage tissue adjacent to the treatment site by dividing thetransmitted laser energy into smaller packets. It can enable selectivetreating and targeting of specific zones encountered by the distal tipof the catheter by activating only the fibers required to heat thosezones. It can reduce the overall power and energy requirements of thetreatment laser by activating smaller portions of fibers in the catheterrather than activating all of the fibers simultaneously. When theinstantaneous energy delivered by laser angioplasty catheters ismaintained below an “adverse effect” threshold, while at the same timedelivering the proper fluence values for tissue ablation, a significantreduction in the incidence of undesirable tissue damage can occur.Previous laser catheters able to energize controllably and selectivelyfibers used fairly complex scan systems including galvanometer scanners(open and closed loop), piezo type deflection devices, and othermechanical beam or coupler deflection systems. These types of systemstypically require a fairly complex and expensive drive and controlsystem. Often, diseased tissue is present in locations where only aportion of the laser catheter's distal tip is in contact with thediseased tissue. It may be desirable to activate only the portion of thedistal tip in contact with the diseased tissue. Additionally, lasercatheters are used to cut or ablate adhesions holding implanted objectsin biological tissue. For safety reasons, it may be desirable to ablateonly the tissue in contact with the laser delivery device tip and toavoid ablating tissue adjacent to the wall or artery to preventperforation.

Notwithstanding these considerations, laser catheters typically energizeall of the fibers simultaneously to achieve bulk ablation. Such fiberactivation outputs energy from all fibers simultaneously. The resultantinstantaneous energy required to achieve the fluence, or energy densityvalues for ablation, can become high enough to induce undesirable tissuedamage, including laser induced dissection.

SUMMARY

These and other needs are addressed by the various aspects, embodiments,and/or configurations of the present disclosure. A method in accordancewith this disclosure can include the steps:

(a) directing a laser beam along an optical path onto a rotating opticalmember and

(b) rotating the optical member to redirect the laser beam from theoptical path onto one or more selected optical fibers of a lasercatheter; and

(c) irradiating, by a distal end of the laser catheter, an endovascularstructure.

A system in accordance with this disclosure can include:

(a) a laser catheter and

(b) a rotating optical member to receive a laser beam along an opticalpath and rotate to a selected position to redirect the laser beam fromthe optical path onto one or more selected optical fibers of a lasercatheter, wherein a distal end of the laser catheter irradiates anendovascular structure.

A tangible, non-transient computer readable medium, in accordance withthis disclosure, can include microprocessor executable instructionsthat, when executed, perform operations comprising:

(a) directing a laser beam along an optical path onto a rotating opticalmember; and

(b) rotating the optical member to redirect the laser beam from theoptical path onto one or more selected optical fibers of a lasercatheter; and

(c) irradiating, by a distal end of the laser catheter, an endovascularstructure.

The rotating optical member can be one or more of a wedge prism, afaceted optic, an axicon, and a parallel faced optic.When the rotating optical member is a parallel faced optic and the laserbeam is incident upon a face of the parallel faced optic, the incidentface can be nonorthogonal to the optical path of the laser beam.

The disclosure can include a detector and/or proximity sensor to sense:

at a first time, a first position of the rotating optical member,wherein at the first position the redirected laser beam irradiates afirst, but not a second, set of optical fibers; and

at a second time, a second position of the rotating optical member,wherein at the second position the redirected laser beam irradiates thesecond, but not the first, set of optical fibers.

The disclosure can include a microprocessor executable controlleroperable to select, based on one or more of total fiber active area ofthe laser catheter, imaging information regarding the target and/ornon-target endovascular structure(s), target endovascular structurecharacterization information, and current location and/or orientation ofa distal tip of the laser catheter, at least one of a fiber active areafor each optical channel, a number of optical channels, a configurationof fibers in an optical channel, an optical channel to be irradiated,and an ordering of optical channel irradiation.

The redirected laser beam can irradiate plural optical fibers positionedalong an arc defined by the laser beam during rotation of the opticalmember.

The present disclosure can provide a number of advantages depending onthe particular aspect, embodiment, and/or configuration. Laser energycan be controllably and selectively delivered onto single fibers orsmaller sub-bundles of subsets of fibers that make up the total numberof fibers that are incorporated into the device. This can reduce theoverall impact of heat or acoustic shock that can damage tissue adjacentto the treatment site by dividing the transmitted laser energy intosmaller packets. It can enable selective treating and targeting ofspecific zones encountered by the distal tip of the catheter byactivating only the fibers required to heat those zones. It can reducethe overall power and energy requirements of the treatment laser byactivating smaller portions of fibers in the catheter rather thanactivating all of the fibers simultaneously. Activating portions of thedistal tip of the catheter using the treatment laser or other diagnosticlight source to probe the area of the lesion contact or tissue diseasetype and/or location to assess the best method or location of the fibersto be activated at the distal end for treatment. This can beaccomplished using a simpler and relatively inexpensive beam deflectionmechanism. By using rotating optics and rotational position monitoringusing encoders or proximity sensors to fire the laser at the exact timethe beam is incident on the target fiber or bundles of fibers, a muchsimpler multiplexed system can be provided. It can eliminate costlygalvanometer scanners and amplifiers with closed loop position feedbackelectronics. A circular multi-fiber coupler can be fabricated easily.Controllable and selective fiber energizing can enable activating onlythe portion of the distal tip in contact with the diseased tissue.Additionally, it can ablate only the tissue in contact with the laserdelivery device tip and avoid ablating tissue adjacent to the wall orartery to prevent perforation. It can avoid providing too muchinstantaneous energy and inducing undesirable tissue damage, includinglaser induced dissection. In other words, it can maintain theinstantaneous energy delivered by laser angioplasty catheters below the“adverse effect” threshold, while at the same time delivering the properfluence values for tissue ablation, thereby providing a significantreduction in the incidence of undesirable tissue damage should occur.

These and other advantages will be apparent from the disclosure.

The phrases “at least one”, “one or more”, and “and/or” are open-endedexpressions that are both conjunctive and disjunctive in operation. Forexample, each of the expressions “at least one of A, B and C”, “at leastone of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B,or C” and “A, B, and/or C” means A alone, B alone, C alone, A and Btogether, A and C together, B and C together, or A, B and C together.

The term “a” or “an” entity refers to one or more of that entity. Assuch, the terms “a” (or “an”), “one or more” and “at least one” can beused interchangeably herein. It is also to be noted that the terms“comprising”, “including”, and “having” can be used interchangeably.

The term “automatic” and variations thereof, as used herein, refers toany process or operation done without material human input when theprocess or operation is performed. However, a process or operation canbe automatic, even though performance of the process or operation usesmaterial or immaterial human input, if the input is received beforeperformance of the process or operation. Human input is deemed to bematerial if such input influences how the process or operation will beperformed. Human input that consents to the performance of the processor operation is not deemed to be “material”.

An “axicon” is an optical element that produces a line image lying alongthe axis from a point source of light; therefore, it has no definitefocal length. An example is a lens with a weak conical surface on oneface.

The term “computer-readable medium” as used herein refers to any storageand/or transmission medium that participate in providing instructions toa processor for execution. Such a medium is commonly tangible andnon-transient and can take many forms, including but not limited to,non-volatile media, volatile media, and transmission media and includeswithout limitation random access memory (“RAM”), read only memory(“ROM”), and the like. Non-volatile media includes, for example, NVRAM,or magnetic or optical disks. Volatile media includes dynamic memory,such as main memory. Common forms of computer-readable media include,for example, a floppy disk (including without limitation a Bernoullicartridge, ZIP drive, and JAZ drive), a flexible disk, hard disk,magnetic tape or cassettes, or any other magnetic medium,magneto-optical medium, a digital video disk (such as CD-ROM), any otheroptical medium, punch cards, paper tape, any other physical medium withpatterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solidstate medium like a memory card, any other memory chip or cartridge, acarrier wave as described hereinafter, or any other medium from which acomputer can read. A digital file attachment to e-mail or otherself-contained information archive or set of archives is considered adistribution medium equivalent to a tangible storage medium. When thecomputer-readable media is configured as a database, it is to beunderstood that the database may be any type of database, such asrelational, hierarchical, object-oriented, and/or the like. Accordingly,the disclosure is considered to include a tangible storage medium ordistribution medium and prior art-recognized equivalents and successormedia, in which the software implementations of the present disclosureare stored. Computer-readable storage medium commonly excludes transientstorage media, particularly electrical, magnetic, electromagnetic,optical, magneto-optical signals.

The terms “determine”, “calculate” and “compute,” and variationsthereof, as used herein, are used interchangeably and include any typeof methodology, process, mathematical operation or technique.

A “laser emitter” refers to an end portion of a fiber or an opticalcomponent that emits laser light from a distal end of the cathetertowards a desired target, which is typically tissue.

A “catheter” is a tube that can be inserted into a body cavity, duct,lumen, or vessel, such as the vasculature system. In most uses, acatheter is a thin, flexible tube (“soft” catheter), though in someuses, it may be a larger, solid less flexible—but possibly stillflexible—catheter (“hard” catheter).

“Coronary catheterization” is a generally minimally invasive procedureto access the coronary circulation and/or blood filled chambers of theheart using a catheter. It is performed for both diagnostic andinterventional (treatment) purposes.

A “coupler” or “fiber optic coupler” refers to the optical fiber devicewith one or more input fibers and one or several output fibers. Fibercouplers are commonly special optical fiber devices with one or moreinput fibers for distributing optical signals into two or more outputfibers. Optical energy is passively split into multiple output signals(fibers), each containing light with properties identical to theoriginal except for reduced amplitude. Fiber couplers have input andoutput configurations defined as M×N. M is the number of input ports(one or more). N is the number of output ports and is always equal to orgreater than M. Fibers can be thermally tapered and fused so that theircores come into intimate contact. This can also be done withpolarization-maintaining fibers, leading to polarization-maintainingcouplers (PM couplers) or splitters. Some couplers use side-polishedfibers, providing access to the fiber core. Couplers can also be madefrom bulk optics, for example in the form of microlenses and beamsplitters, which can be coupled to fibers (“fiber pig-tailed”).

“Electromagnetic radiation” or “EM radiation” or “EMR” is a form ofenergy emitted and absorbed by charged particles which exhibitswave-like behavior as it travels through space. EMR has both electricand magnetic field components, which stand in a fixed ratio of intensityto each other, and which oscillate in phase perpendicular to each otherand perpendicular to the direction of energy and wave propagation. Theelectromagnetic spectrum, in order of increasing frequency anddecreasing wavelength, consists of radio waves, microwaves, infraredradiation, visible light, ultraviolet radiation, X-rays and gamma rays.

A “lead” is a conductive structure, typically an electrically insulatedcoiled wire. The electrically conductive material can be any conductivematerial, with metals and intermetallic alloys common. The outer sheathof insulative material is biocompatible and biostable (e.g.,non-dissolving in the body) and generally includes organic materialssuch as polyurethane and polyimide. Lead types include, by way ofnon-limiting example, epicardial and endocardial leads. Leads arecommonly implanted into a body percutaneously or surgically.

The term “means” as used herein shall be given its broadest possibleinterpretation in accordance with 35 U.S.C., Section 112, Paragraph 6.Accordingly, a claim incorporating the term “means” shall cover allstructures, materials, or acts set forth herein, and all of theequivalents thereof. Further, the structures, materials or acts and theequivalents thereof shall include all those described in the summary ofthe invention, brief description of the drawings, detailed description,abstract, and claims themselves.

The term “module” as used herein refers to any known or later developedhardware, software, firmware, artificial intelligence, fuzzy logic, orcombination of hardware and software that is capable of performing thefunctionality associated with that element. Also, while the disclosureis presented in terms of exemplary embodiments, it should be appreciatedthat individual aspects of the disclosure can be separately claimed.

An “optical fiber” or “laser active fiber” is a flexible, transparentfiber made of an optically transmissive material, such as glass (silica)or plastic that functions as a waveguide, or “light pipe”, to transmitlight between the two ends of the fiber.

A “surgical implant” is a medical device manufactured to replace amissing biological structure, support, stimulate, or treat a damagedbiological structure, or enhance, stimulate, or treat an existingbiological structure. Medical implants are man-made devices, in contrastto a transplant, which is a transplanted biomedical tissue. In somecases implants contain electronics, including, without limitation,artificial pacemaker, defibrillator, electrodes, and cochlear implants.Some implants are bioactive, including, without limitation, subcutaneousdrug delivery devices in the form of implantable pills or drug-elutingstents.

The preceding is a simplified summary of the disclosure to provide anunderstanding of some aspects of the disclosure. This summary is neitheran extensive nor exhaustive overview of the disclosure and its variousaspects, embodiments, and/or configurations. It is intended neither toidentify key or critical elements of the disclosure nor to delineate thescope of the disclosure but to present selected concepts of thedisclosure in a simplified form as an introduction to the more detaileddescription presented below. As will be appreciated, other aspects,embodiments, and/or configurations of the disclosure are possibleutilizing, alone or in combination, one or more of the features setforth above or described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a distal tip of a laser catheter containing a lumen;

FIG. 2 depicts a distal tip of a lumenless laser catheter;

FIG. 3 is a cross-sectional view of the distal tip of FIG. 1 approachingtarget tissue or other endovascular structure;

FIG. 4 is a block diagram of a multiplexed laser catheter according toan embodiment;

FIG. 5 is a block diagram of a multiplexed laser catheter according toan embodiment;

FIG. 6 is a block diagram of a control system according to anembodiment;

FIGS. 7A-B depict a fiber array according to an embodiment;

FIG. 8 depicts a multiplexing system according to an embodiment;

FIGS. 9A-C depict a fiber array according to an embodiment;

FIG. 10 depicts a control algorithm according to an embodiment; and

FIG. 11 depicts a first energizing mode;

FIGS. 12A-B depict a second energizing mode;

FIGS. 13A-C depict a third energizing mode; and

FIGS. 14A-D depict a fourth energizing mode.

DETAILED DESCRIPTION

FIGS. 1 and 2 depict the working or distal ends of various known priorart laser catheters having plural optical fibers 324 embedded therein.FIG. 1 shows a flexible catheter 100 comprising a catheter lumen 104 toreceive an implanted lead or guide wire (not shown) and plural laseremitters 108 positioned around the periphery or diameter of the catheterlumen 104. This type of catheter assembly is sold as a coronary laseratherectomy catheter by the Spectranetics Corporation under thetradenames ELCA™ and Turbo Elite™ (each of which is used for coronaryintervention or catheterization such as recanalizing occluded arteries,changing lesion morphology, and facilitating stent placement) and as alaser sheath under the tradename SLSII™ and GlideLight™ (which is usedfor surgically implanted lead removal). FIG. 2 shows a flexible catheter200 comprising plural laser emitters 108 packed into the distal end ofthe catheter. The number of rows of optical fibers and emitters locatedin the catheter and/or located concentrically around the lumen and thenumber of optical fibers and emitters in each row can vary byapplication and are not limited to the depicted configurations. Theprimary difference between the catheters in FIGS. 1 and 2 is the absenceof a catheter lumen 104 in the catheter of FIG. 2.

Referring to FIG. 3, a laser ablation catheter 300 is positioned in abody lumen 304, such as a blood vessel, to remove a complete or partialocclusion 308. A guide wire 312 passes through the body lumen 304 andocclusion 308 on the one hand and the catheter lumen 316 formed by asubstantially cylindrical inner catheter surface 320 on the other toguide the catheter to the occlusion 308. Laser emitters 108 arepositioned at the distal end of the catheter to ablate the occlusion.Optical fiber 324 connects a corresponding emitter to the laser via theproximal end or coupler (FIG. 8).

FIG. 8 depicts a laser assembly 800 including a laser 804, such as alow-temperature excimer laser operating in the ultraviolet spectrum ataround 308 nm, a lens assembly 824 (which includes one or more lensesand/or filters), a fiber selector 808 to controllably and selectivelyenergize fibers 108, a coupler 812 to couple to a proximal end of thelaser catheter 300, and plural optical channels, each channel beingrepresented by a corresponding first, second, third, . . . nth opticfiber set 818 a-n. The laser 804 emits laser energy or beam 828, whichis directed by the laser assembly 800 to the fiber selector 808. Thefiber selector 808 directs the laser energy 828, through the coupler812, and onto a selected one of the first, second, third, . . . nthoptic fiber set 818 a-n. As will be appreciated, the laser 804 can bethe same for both treatment and diagnostic laser pulses or differentlasers may be employed. When compared to treatment laser pulses,diagnostic laser pulses use lower power.

FIG. 6 depicts a control system 600 according to an embodiment. Thecontrol system 600 includes a controller 604 (which is typically amicroprocessor) in signal and electrical communication with a memory608, laser circuitry 612 to operate the laser 804, a user interface 616to receive commands from and provide queries, target tissue or otherendovascular structure information, and other feedback to a user, atarget acquisition module 620 to determine target tissue or otherendovascular structure location and/or characterization information, adetector 624 to select an optical channel from among plural opticalchannels for energization, scanner drive electronics 628 to operate thefiber selector 808 for energizing selected optical channels, and anoptional catheter size information receiver 632 to receive informationregarding the total fiber active area at the distal tip of the catheter.The controller 604 can use target tissue or other endovascular structurelocation and other imaging or diagnostic information, target tissue orother endovascular structure characterization information (such astissue density, type, location, and configuration) and/or target tissueor other endovascular structure proximity to other non-target tissuestructures, such as blood vessel walls, and total fiber active area atthe distal end or tip to select not only laser parameters (such as, foreach selected optical channel, fluence, energy density value, intensity,an active area, a maximum allowable fluence, a minimum allowablefluence, repetition rate (e.g., lasing on/off time), and lasing traintime) but also the number of optical channels, the fiber active area foreach optical channel, the fiber configuration for each optical channel,the specific optical channels to energize for target tissue ablation,and the sequence for energizing the selected channels.

The memory 608 can be any computer readable medium and stores, for acurrent catheterization procedure, a variety of information, includingtarget tissue or other endovascular structure location, characterizationinformation, target tissue or other endovascular structure proximity tonon-target tissue structures and other imaging information, laserparameters, optical channel number and configuration, optical channelenergizing sequence or ordering, patient information, total fiber activearea of the distal end or tip, timestamps, and the like. It can alsostore various look up tables to enable the controller 604 to configurethe optical channels for a currently connected catheter based on thetotal fiber active area of the catheter. Thus, different models or typesor configurations of catheters having different total fiber active areascan have different numbers and configurations of optical channels.

Laser circuitry 612 enables operation of the laser by the controller 604in response to user commands received by the user interface 616. Thelaser circuitry 612 is conventional.

The user interface 616 can be any audio, video, and/or tactileinterface, such as a keyboard, display, microphone, and the like.

The target acquisition module 620 acquires imaging information via atarget imaging (and/or diagnostic) module 636 (hereinafter referred toas target imaging module 636). The imaging information relates not onlyto the structure of the target tissue or other endovascular structure,such as an occlusion, unwanted tissue growth in proximity to asurgically implanted structure, and the like but also to non-targettissue structures in proximity to the target tissue structure. Thetarget imaging module 636 can be any suitable imaging device, such as,but not limited to, laser induced fluorescence spectroscopy, opticalcoherence reflectometry, optical coherence tomography, and Ramanspectroscopy. The imaging information can be a two, three, or fourdimensional representation of the imaged tissue structures.

The detector 624 operatively engages the fiber selector 808 to determinea current optical channel positioned for energizing by the laser and/ora position of a selected optical channel relative to a desired positionfor the optical channel. The detector 624 can be any suitableconfiguration, whether a mechanical, optical, electrical, and/orelectromagnetic device for tracking movement and/or a current positionof the fiber selector 808. It can also be configured as one or moreproximity sensors to fire the laser at the precise time that the beam isincident on the target fibers or bundles (or set) of fibers.

The scanner drive electronics 628 one or more of controllably directsthe laser beam in a desired orientation and/or controls movement of thefiber selector 808. An example of the former configuration is describedin U.S. Pat. No. 5,400,428 to Grace, which is incorporated herein bythis reference. Grace discloses a dielectric mirror mounted on agalvanometer scanner that is moved to cause successive laser pulses toirradiate different optical channels, thereby enabling each fiber toreceive radiation having sufficient fluence while reducing the energyper pulse (or the cw equivalent). Examples of the latter configurationare discussed below.

The catheter size information receiver 632 can be any configuration. Forexample, it can be based on a lookup table using an identifier of thecatheter. The identifier can be provided by a pin sequence orconfiguration on the proximal end of the catheter. The sequence and/orconfiguration of pins is mounted to the proximal end of the catheter.The pin arrangement or sequence actuates switches in the catheter'scoupler to generate a signal, which is forwarded to the controller 604.Using a lookup table in memory 608 and the signal, the controller 604can identify the type and/or model of the catheter and therefore theappropriate catheter specifications, requirements, and other operatinginformation. Each type and/or model of catheter has a unique pinsequence to actuate different switches for generating different signals.Other techniques for providing the identifier to the controller 604 mayalso be employed, such as the techniques discussed in copending U.S.patent application Ser. No. ______, filed concurrently herewith,entitled “Intelligent Catheter”, and having Attorney Docket No.6593-235, which is incorporated herein by reference in its entirety.

Various configurations of the fiber selector 808 will now be discussedwith reference to FIGS. 4-5, 7A-B, and 9A-C. Although the fiber selector808 is shown as being distal to the coupler, it may be positioned withinor proximal to the coupler, depending on the application.

Referring to FIG. 4, a first fiber selector configuration is depicted.While FIG. 4 and other figures depict the optical fibers as a lineararray for purposes of simplicity, it is to be understood that otherfiber arrangements can be employed, particularly fibers oriented in athree dimensional array.

The fiber selector 808 comprises a rotating wedge optical member 400positioned in the optical path 404 of the laser beam 408 to redirect, byoptical refraction, the laser beam onto one or more selected fibers 324,with the optical fiber(s) irradiated at any one time corresponding to anoptical channel and optical fiber(s) irradiated at different timescorresponding to different optical channels. As will be appreciated, awedge prism can be uncoated or coated with an anti-reflection coatingand can deviate an angle of an incident beam. Typically, the wedge prismdeviates the angle of the laser beam by an amount ranging from about 70to about 20 degrees. The wedge optical member 400 typically has athickness that is dependent upon the desired beam deviation, which is aalso a function of the size of the coupler. This causes the laser beam408 to be diverted at an angle Ω 428 relative to the optical path 404along a diverging optical path. The motor-driven rotation of the opticalmember can be at fixed and/or variable speeds.

Alternatively, plural wedge optical members can be used to redirect thelaser beam. For example, two wedge prisms can be used as an anamorphicpair to steer the beam anywhere within a circle described by the fullangle 40, where θ is the deviation from a single prism. This beamsteering is accomplished by rotating the two wedge prisms independentlyof each other.

The position of the wedge optical member 400 can be determined by thedetector 624 based upon, for example, radiation reflected by a locatingmember 432, which rotates simultaneously and in an amount related torotation of the wedge optical member 400. For example, the locatingmember 432 can be encoded with encoding elements that reflect lightuniquely or substantially uniquely for any position around thecircumference of the locating member 432. To produce the unique lightreflectance can be the result of the encoding elements being differentlysized, spaced, and/or colored. An example of such encoding elements is abar code. The detector 624 emits light onto the locating member, detectsthe reflected spectra, and maps the reflected spectra against a lookuptable that indexes each absolute and/or relative position around thelocating member 432 against a corresponding set of reflected spectra.Based on the comparison, a locating signal is generated and sent to thecontroller 604, which then instructs a subcontroller (not shown), whichfurther instructs the motor (not shown) to rotate the wedge opticalmember 400 a selected angle to align the selected optical channel withthe redirected laser beam 408. By incorporating the optical encoder, thelaser can be fired at the time the beam is deflected to the position tocouple into the desired fiber or bundle of fibers. While tracking theposition of the wedge optical member 400 is discussed with reference toan optical encoder, other types of encoders may be employed, such asmechanical, electrical, and/or electromagnetic position trackingdevices.

Referring to FIG. 5, a second fiber selector configuration is depicted.The fiber selector 808 comprises a rotating parallel-faced opticalmember 500 positioned in the optical path 404 of the laser beam 408 toredirect, by optical refraction, the laser beam onto one or moreselected fibers 324. The parallel-faced optical member 500 comprisesopposing parallel faces 504 and 508 and is inclined relative to theoptical path 404 at an angle δ 512 sufficient to deviate the laser beam408 from the optical path 408 by an angle ranging from about 70 to about20 degrees. The optical member 500 typically has a thickness that isdependent upon the desired beam deviation, which is a also a function ofthe size of the coupler. The inclined parallel surfaces 504 and 512cause the laser beam 408 to be diverted and offset relative to andsubstantially parallel to the optical path 404.

In the first and second fiber selector configurations, the direction ofrotation, whether clockwise, counterclockwise or both, is a matter ofdesign choice.

In each of the first and second fiber selector configurations, completerotation of the optical member causes the laser beam to trace, ordefine, a circle on the optical fibers. Partial rotation of the opticalmember causes the laser beam to trace a partial circle, with the lengthof the arc being proportional to the degree of rotation of the opticalmember. Any optical fiber positioned along the arc is irradiated by theincident redirected laser beam.

Other types of optical members may be used. For example, a facetedoptical member, known as an axicon, may also be employed. In anotherexample, a faceted optical element is employed.

Referring to FIGS. 7A-B, a third fiber selector configuration isdepicted. This configuration is further discussed in U.S. Pat. No.5,400,428 referenced above.

A grooved fiber holder 700 holds two equally sized bundles of fibers 818a,b, each bundle corresponding to a different optical channel. Bundles818 a,b are centered upon the same linear transverse axis 704. The laserbeam is focused so that the first incident beam pulse irradiates all offiber bundle 818 b (FIG. 7A), which is half of the total fibers. Eitherthe beam or the fibers are then shifted so that next pulse of the laserbeam is focused on bundle 818 a (FIG. 7B). The grooved fiber holder 700can be translated along the linear transverse axis 704 by displacing theholder 700 laterally in a carrier member 708, such as energizing apiezoelectric stack or a motor.

Referring to FIGS. 9A-C, a fourth fiber selector configuration isdepicted. FIGS. 9A-C illustrate three bundles of optical fibers 818 a,818 b and 818 c, each bundle corresponding to a different opticalchannel. Each bundle of fibers 818 a, 818 b and 818 c contains ⅓ of thetotal number of fibers. The optical fiber bundles are disposed in agrooved fiber holder 900 that moves laterally within a holder 904 asdiscussed above. First scan position (FIG. 9A) irradiates fiber bundle818 a. In a second scan position (FIG. 9B), the beam and fibers aremoved relative to one another to irradiate the second fiber bundle 818b. In a third scan position (FIG. 9C), the next laser pulse is directedat the third bundle of optical fibers 818 c. As in FIG. 5 a, the fiberbundles are disposed in a linear manner along the same transverse axis320 to provide for linear scanning

As will be appreciated, other fiber selector configurations may beemployed.

Regardless of the fiber selector configuration employed, the distal endor tip of the catheter energizes all or part of the laser emitters 108as shown in FIGS. 11, 12A-B, 13A-C, and 14A-D. As noted, the portion ofthe laser emitters 108 energized, or the number of optical channelsemployed, depend on one or more of target tissue or other endovascularstructure location, target tissue or other endovascular structurecharacterization information (such as tissue density, type, location,and configuration), current location and/or orientation of the distaltip of the catheter, and/or target tissue or other endovascularstructure proximity to other non-target tissue structures, and totalfiber active area at the distal end or tip. In FIGS. 11, 12A-B, 13A-C,and 14A-D, darkened laser emitters refer to those being energized whileundarkened laser emitters refer to those not being energized.

FIG. 11 depicts a first operating mode in which all of the laseremitters 108 in the distal tip of the catheter are energizedsimultaneously.

FIGS. 12A-B depict a second operating mode for a 2-way multiplexingconfiguration in which one-half of the laser emitters 108 are energizedsimultaneously at a first time and the other half of the laser emitters108 are energized simultaneously at a second (different) time. Thisoperating mode can be produced by any of the first, second, and thirdfiber selector configurations.

FIGS. 13A-C depict a third operating mode for a 3-way multiplexingconfiguration in which a first one-third of the laser emitters 108 isenergized simultaneously at a first time, a second one-third of thelaser emitters 108 is energized simultaneously at a second time, and athird one-third of the laser emitters 108 is energized simultaneously ata third time. The first, second, and third times are different. Thisoperating mode can be produced by any of the first, second, and fourthfiber selector configurations.

FIGS. 14A-D depict a fourth operating mode for a 4-way multiplexingconfiguration in which a first one-quarter of the laser emitters 108 isenergized simultaneously at a first time, a second one-quarter of thelaser emitters 108 is energized simultaneously at a second time, a thirdone-quarter of the laser emitters 108 is energized simultaneously at athird time, and a fourth one-quarter of the laser emitters 108 isenergized simultaneously at a fourth time. The first, second, third, andfourth times are different. This operating mode can be produced by anyof the first and second fiber selector configurations.

As will be appreciated, multiplexing may be performed up to N ways, withN being a whole number. Multiplexing is not limited to 2, 3, and 4 waysas shown in the above figures.

As will be further appreciated, the geometrical pattern of laseremitters 108 energized can be different from those shown. The laseremitters 108 can be energized along an arc, be randomly distributed,and/or be uniformly or nonuniformly distributed around the circumferenceof the distal tip of the catheter.

An operation of the controller 604 will now be described with referenceto FIG. 10.

The operation commences in step 1000 in which the controller 604 detectsa stimulus. The stimulus can be, for example, a command received from anoperator, such as a physician, via the user interface 616.

The controller 604 determines a total fiber active area of the cathetercurrently coupled to the coupler 812.

The controller 604, in step 1008, selects a number of optical channelsbased on the determined total fiber active area. As noted, this can bedone using a lookup table. In other configurations, the controller 604can use other information, particularly imaging information (includingtarget tissue or other endovascular structure location, target tissue orother endovascular structure characterization information (such astissue density, type, location, and configuration), current locationand/or orientation of the distal tip of the catheter, and/or targettissue or other endovascular structure proximity to other non-targettissue structures) received from the target acquisition module 620 inaddition to or lieu of the total fiber active area in selecting thenumber of optical channels. In that event, step 1008 would follow step1012.

In one application, the controller 604 selects one or more of a fiberactive area for each optical channel, a number of optical channels, aconfiguration of fibers in an optical channel, an optical channel to beirradiated, and an ordering of optical channel irradiation based on oneor more of total fiber active area of the laser catheter, imaginginformation regarding the target and/or non-target endovascularstructure(s), target endovascular structure characterizationinformation, and current location and/or orientation of a distal tip ofthe laser catheter.

In step 1012, the controller 604 receives target acquisition informationfrom the target acquisition module 620 and indirectly from the targetimaging module 636. The target acquisition information is typicallyimaging information. In some configurations, additional wavelengths oflight are launched down the fibers and through the laser emitters in thecatheter and returned or reflected light analyzed to determinereflectivity and absorption data. This can be used to determine targetand/or non-target tissue or other endovascular structure location, type,and/or contact area (area of contact between the distal tip andstructure of the target tissue or other endovascular structure).

In step 1016, the controller 604 selects which of the optical channelsto energize to ablate the target tissue or other endovascular structure.This can be determined based upon any or all of the informationreferenced in the prior paragraph and/or user input.

In step 1020, the controller 604 determines an energization sequence.The sequence governs which optical channels are energized and in whatorder and times. This can be determined based upon any or all of theinformation referenced previously including imaging information and userinput.

In step 1024, the controller 604 initiates optical channel energizationin accordance with the determined energization sequence.

The exemplary systems and methods of this disclosure have been describedin relation to a laser catheter. However, to avoid unnecessarilyobscuring the present disclosure, the preceding description omits anumber of known structures and devices. This omission is not to beconstrued as a limitation of the scopes of the claims. Specific detailsare set forth to provide an understanding of the present disclosure. Itshould however be appreciated that the present disclosure may bepracticed in a variety of ways beyond the specific detail set forthherein.

Furthermore, while the exemplary aspects, embodiments, and/orconfigurations illustrated herein show the various components of thesystem collocated, certain components of the system can be locatedremotely, at distant portions of a distributed network, such as a LANand/or the Internet, or within a dedicated system. Thus, it should beappreciated, that the components of the system can be combined in to oneor more devices, such as a base unit, or collocated on a particular nodeof a distributed network.

Furthermore, it should be appreciated that the various links connectingthe elements can be wired or wireless links, or any combination thereof,or any other known or later developed element(s) that is capable ofsupplying and/or communicating data to and from the connected elements.These wired or wireless links can also be secure links and may becapable of communicating encrypted information. Transmission media usedas links, for example, can be any suitable carrier for electricalsignals, including coaxial cables, copper wire and fiber optics, and maytake the form of acoustic or light waves, such as those generated duringradio-wave and infra-red data communications.

Also, while the flowcharts have been discussed and illustrated inrelation to a particular sequence of events, it should be appreciatedthat changes, additions, and omissions to this sequence can occurwithout materially affecting the operation of the disclosed embodiments,configuration, and aspects.

A number of variations and modifications of the disclosure can be used.It would be possible to provide for some features of the disclosurewithout providing others.

For example, the systems and methods of this disclosure can beimplemented in conjunction with a special purpose computer, a programmedmicroprocessor or microcontroller and peripheral integrated circuitelement(s), an ASIC or other integrated circuit, a digital signalprocessor, a hard-wired electronic or logic circuit such as discreteelement circuit, a programmable logic device or gate array such as PLD,PLA, FPGA, PAL, special purpose computer, any comparable means, or thelike. In general, any device(s) or means capable of implementing themethodology illustrated herein can be used to implement the variousaspects of this disclosure. Exemplary hardware that can be used for thedisclosed embodiments, configurations and aspects includes computers,handheld devices, telephones (e.g., cellular, Internet enabled, digital,analog, hybrids, and others), and other hardware known in the art. Someof these devices include processors (e.g., a single or multiplemicroprocessors), memory, nonvolatile storage, input devices, and outputdevices. Furthermore, alternative software implementations including,but not limited to, distributed processing or component/objectdistributed processing, parallel processing, or virtual machineprocessing can also be constructed to implement the methods describedherein.

In yet another embodiment, the disclosed methods may be readilyimplemented in conjunction with software using object or object-orientedsoftware development environments that provide portable source code thatcan be used on a variety of computer or workstation platforms.Alternatively, the disclosed system may be implemented partially orfully in hardware using standard logic circuits or VLSI design. Whethersoftware or hardware is used to implement the systems in accordance withthis disclosure is dependent on the speed and/or efficiency requirementsof the system, the particular function, and the particular software orhardware systems or microprocessor or microcomputer systems beingutilized.

In yet another embodiment, the disclosed methods may be partiallyimplemented in software that can be stored on a storage medium, executedon programmed general-purpose computer with the cooperation of acontroller and memory, a special purpose computer, a microprocessor, orthe like. In these instances, the systems and methods of this disclosurecan be implemented as program embedded on personal computer such as anapplet, JAVA® or CGI script, as a resource residing on a server orcomputer workstation, as a routine embedded in a dedicated measurementsystem, system component, or the like. The system can also beimplemented by physically incorporating the system and/or method into asoftware and/or hardware system.

Although the present disclosure describes components and functionsimplemented in the aspects, embodiments, and/or configurations withreference to particular standards and protocols, the aspects,embodiments, and/or configurations are not limited to such standards andprotocols. Other similar standards and protocols not mentioned hereinare in existence and are considered to be included in the presentdisclosure. Moreover, the standards and protocols mentioned herein andother similar standards and protocols not mentioned herein areperiodically superseded by faster or more effective equivalents havingessentially the same functions. Such replacement standards and protocolshaving the same functions are considered equivalents included in thepresent disclosure.

The present disclosure, in various aspects, embodiments, and/orconfigurations, includes components, methods, processes, systems and/orapparatus substantially as depicted and described herein, includingvarious aspects, embodiments, configurations embodiments,subcombinations, and/or subsets thereof. Those of skill in the art willunderstand how to make and use the disclosed aspects, embodiments,and/or configurations after understanding the present disclosure. Thepresent disclosure, in various aspects, embodiments, and/orconfigurations, includes providing devices and processes in the absenceof items not depicted and/or described herein or in various aspects,embodiments, and/or configurations hereof, including in the absence ofsuch items as may have been used in previous devices or processes, e.g.,for improving performance, achieving ease and\or reducing cost ofimplementation.

The foregoing discussion has been presented for purposes of illustrationand description. The foregoing is not intended to limit the disclosureto the form or forms disclosed herein. In the foregoing DetailedDescription for example, various features of the disclosure are groupedtogether in one or more aspects, embodiments, and/or configurations forthe purpose of streamlining the disclosure. The features of the aspects,embodiments, and/or configurations of the disclosure may be combined inalternate aspects, embodiments, and/or configurations other than thosediscussed above. This method of disclosure is not to be interpreted asreflecting an intention that the claims require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive aspects lie in less than all features of a singleforegoing disclosed aspect, embodiment, and/or configuration. Thus, thefollowing claims are hereby incorporated into this Detailed Description,with each claim standing on its own as a separate preferred embodimentof the disclosure.

Moreover, though the description has included description of one or moreaspects, embodiments, and/or configurations and certain variations andmodifications, other variations, combinations, and modifications arewithin the scope of the disclosure, e.g., as may be within the skill andknowledge of those in the art, after understanding the presentdisclosure. It is intended to obtain rights which include alternativeaspects, embodiments, and/or configurations to the extent permitted,including alternate, interchangeable and/or equivalent structures,functions, ranges or steps to those claimed, whether or not suchalternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

What is claimed is:
 1. A method, comprising: directing a laser beamalong an optical path onto a rotating optical member; and rotating theoptical member to redirect the laser beam from the optical path onto oneor more selected optical fibers of a laser catheter; and irradiating, bya distal end of the laser catheter, an endovascular structure.
 2. Themethod of claim 1, wherein the rotating optical member is one or more ofa wedge prism, a faceted optic, an axicon, and a parallel faced optic.3. The method of claim 2, wherein the rotating optical member is aparallel faced optic, wherein the laser beam is incident upon a face ofthe parallel faced optic, and wherein the incident face is nonorthogonalto the optical path of the laser beam.
 4. The method of claim 1, furthercomprising: sensing, by at least one of a detector and proximity sensorand at a first time, a first position of the rotating optical member,wherein at the first position the redirected laser beam irradiates afirst, but not a second, set of optical fibers; and sensing, by the atleast one of a detector and proximity sensor and at a second time, asecond position of the rotating optical member, wherein at the secondposition the redirected laser beam irradiates the second, but not thefirst, set of optical fibers.
 5. The method of claim 1, furthercomprising: selecting, by a microprocessor executable controller andbased on one or more of total fiber active area of the laser catheter,imaging information regarding the target and/or non-target endovascularstructure(s), target endovascular structure characterizationinformation, and current location and/or orientation of a distal tip ofthe laser catheter, at least one of a fiber active area for each opticalchannel, a number of optical channels, a configuration of fibers in anoptical channel, an optical channel to be irradiated, and an ordering ofoptical channel irradiation.
 6. The method of claim 1, wherein theredirected laser beam irradiates plural optical fibers positioned alongan arc defined by the laser beam during rotation of the optical member.7. A system, comprising: a laser catheter; and a rotating optical memberto receive a laser beam along an optical path and rotate to a selectedposition to redirect the laser beam from the optical path onto one ormore selected optical fibers of a laser catheter, wherein a distal endof the laser catheter irradiates an endovascular structure.
 8. Thesystem of claim 7, wherein the rotating optical member is one or more ofa wedge prism, a faceted optic, an axicon, and a parallel faced optic.9. The system of claim 8, wherein the rotating optical member is aparallel faced optic, wherein the laser beam is incident upon a face ofthe parallel faced optic, and wherein the incident face is nonorthogonalto the optical path of the laser beam.
 10. The system of claim 7,further comprising: at least one of a detector and proximity sensor tosense: at a first time, a first position of the rotating optical member,wherein at the first position the redirected laser beam irradiates afirst, but not a second, set of optical fibers; and at a second time, asecond position of the rotating optical member, wherein at the secondposition the redirected laser beam irradiates the second, but not thefirst, set of optical fibers.
 11. The system of claim 7, furthercomprising: a microprocessor executable controller operable to select,based on one or more of total fiber active area of the laser catheter,imaging information regarding the target and/or non-target endovascularstructure(s), target endovascular structure characterizationinformation, and current location and/or orientation of a distal tip ofthe laser catheter, at least one of a fiber active area for each opticalchannel, a number of optical channels, a configuration of fibers in anoptical channel, an optical channel to be irradiated, and an ordering ofoptical channel irradiation.
 12. The system of claim 7, wherein theredirected laser beam irradiates plural optical fibers positioned alongan arc defined by the laser beam during rotation of the optical member.13. A tangible, non-transient computer readable medium comprisingmicroprocessor executable instructions that, when executed, performoperations comprising: directing a laser beam along an optical path ontoa rotating optical member; and rotating the optical member to redirectthe laser beam from the optical path onto one or more selected opticalfibers of a laser catheter; and irradiating, by a distal end of thelaser catheter, an endovascular structure.
 14. The computer readablemedium of claim 13, wherein the rotating optical member is one or moreof a wedge prism, a faceted optic, an axicon, and a parallel facedoptic.
 15. The computer readable medium of claim 14, wherein therotating optical member is a parallel faced optic, wherein the laserbeam is incident upon a face of the parallel faced optic, and whereinthe incident face is nonorthogonal to the optical path of the laserbeam.
 16. The computer readable medium of claim 13, further comprising:sensing, by at least one of a detector and proximity sensor and at afirst time, a first position of the rotating optical member, wherein atthe first position the redirected laser beam irradiates a first, but nota second, set of optical fibers; and sensing, by the at least one of adetector and proximity sensor and at a second time, a second position ofthe rotating optical member, wherein at the second position theredirected laser beam irradiates the second, but not the first, set ofoptical fibers.
 17. The computer readable medium of claim 13, furthercomprising: selecting, based on one or more of total fiber active areaof the laser catheter, imaging information regarding the target and/ornon-target endovascular structure(s), target endovascular structurecharacterization information, and current location and/or orientation ofa distal tip of the laser catheter, at least one of a fiber active areafor each optical channel, a number of optical channels, a configurationof fibers in an optical channel, an optical channel to be irradiated,and an ordering of optical channel irradiation.
 18. The computerreadable medium of claim 13, wherein the redirected laser beamirradiates plural optical fibers positioned along an arc defined by thelaser beam during rotation of the optical member.